Microcontroller Voltage Measurement Circuit for Small Voltage Differences
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Solution Overview
Problem
Conventional microcontroller-based voltage measurement circuits are limited to a fixed measurement range, resulting in reduced relative resolution for small voltage variations and require pre-amplification, which degrades accuracy and increases complexity.
Innovation Solution
A voltage measurement arrangement using a microcontroller with a comparator, RC network, and switching device to alternately apply reference and measurement voltages to the comparator inputs, enabling high-resolution measurements in arbitrarily selectable ranges without additional amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed measurement range is used in conventional microcontroller voltage measurement circuits, then the circuit structure is simple, but the measurement precision is reduced for small voltage variations
Solution Approach 1:
The patent implements a dynamically adjustable measurement range by allowing the microcontroller to programmatically select different voltage ranges through configuration registers. This enables the system to adapt the measurement scale to the specific application requirements, thereby improving relative resolution for small voltage variations without requiring multiple fixed-range circuits.
Solution Approach 2:
The invention changes the measurement parameters (voltage range, resolution, scaling factors) through software configuration rather than hardware modification. The microcontroller can be programmed to adjust the measurement range and corresponding resolution dynamically, providing high precision for small voltage variations while maintaining a simple unified circuit structure.
2Measurement precision
If pre-amplification is used to measure small voltage differences, then the measurement precision improves, but gain and offset errors are introduced
Solution Approach 1:
The patent replaces the mechanical/electronic amplification system with a software-based measurement and calculation system. Instead of using pre-amplification circuits that introduce gain and offset errors, the invention directly measures small voltage differences using the microcontroller's built-in ADC and processes the data through software algorithms, thereby eliminating amplification-related errors while maintaining measurement precision.
Solution Approach 2:
The invention introduces a software intermediary layer between the voltage measurement and the final result. The microcontroller's ADC directly measures the voltage, and then software performs the necessary calculations and scaling to achieve the desired measurement precision without physical amplification, thus avoiding gain and offset errors introduced by amplifier circuits.
3Measurement precision
If the measurement range is reduced to focus on small voltage variations, then the relative resolution improves, but the adaptability to different applications decreases
Solution Approach 1:
The patent creates a universal voltage measurement system that can function across multiple measurement ranges and applications. The microcontroller is programmed to support various measurement ranges (e.g., 0-3V, 0-5V, 0-12V) with different resolutions, allowing the same hardware circuit to be adapted to different applications by simply changing software configuration, thereby achieving both high relative resolution and broad adaptability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise voltage measurement with adjustable ranges and high resolution, reducing complexity and avoiding gain and offset errors by directly measuring small voltage differences.
Implementation Method 1
an RC network consisting of at least one resistor and at least one capacitor, wherein the at least one capacitor is charged and discharged depending on a level of the comparator output signal
Implementation Method 2
an RC network consisting of at least one resistor and at least one capacitor, wherein the at least one capacitor is charged and discharged depending on a level of the comparator output signal, in particular via the resistor
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a voltage measurement arrangement (1), in particular for use with a microcontroller, for measuring and digitizing a measurement voltage potential or a measurement voltage (Umeas) with high precision, comprising: - an adjustable reference voltage source (24) for providing a reference voltage potential or a reference voltage (Uref), - a comparator (21) with a first input (CMP_IN+), a second input and a comparator output for outputting a high level or a low level of a comparator output signal depending on the sign of a voltage difference between the first and the second input (CMP_IN+, CMP_IN-); - an RC network (4) comprising at least one resistor (R) and at least one capacitor (C), wherein the at least one capacitor (C) is charged and discharged depending on the level of the comparator output signal;- a switching device (22) for alternately applying the reference voltage potential or reference voltage (Uref) or the measurement voltage potential or measurement voltage (Umess) to the first input (CMP _IN+) of the comparator (21), so that a cyclic charging and discharging of the at least one capacitor (C) is achieved, and - a time or frequency measuring unit (23) for measuring a period or a frequency of a periodic comparator output signal as an indication of the measurement voltage potential or measurement voltage (Umess).;